Cesar Zamora, an 18-year-old outside midfielder and defender who was promoted from Chivas USA's development team to its first team in late May, has been added to the U.S. under-20 national team for its trip to Argentina.

Zamora was the third former Chivas USA youth player promoted to the MLS club's first-team roster, alongside Gerson Mayen and Jorge Flores.

Mayen and Flores are with the U-20s for their trip to the Copa Ciudad de Rosario. Flores also played with the U-20s in Concacaf qualifying for the Under-20 World Cup, beginning in late September.